Organoleads lead acetates

Acute lead exposure can lead to renal toxicity. The acute intraperitoneal LD50 for lead acetate in rodents is 100-200 mg kg Lead acetate is considerably less toxic by the oral route (LD5o>4gkg in rats). The acute oral LD50 of tetraethyl lead in rodents is 10-100 mg kg Acute organolead exposure can... 

Many papers report the formation of lead-containing polymers but the formulations do not necessarily produce lead covalently bonded as part of a polymer. For instance, Honda and Kaetsu described the production of a transparent, easily moldable polymer useful for protection against radiation by dissolving a specified amount of an organolead compormd in a specified monomer ntixture. Thus lead acetate is dissolved in a monomer mixture containing methyl methacrylate, methacrylic acid, and a-methyl styrene, and free-radical s polymerization carried out. The resulting mixture is sandwiched between glass plates to obtain the desired product. 

Fig. 1. LC—ICP-MS chromatogram of a standard mixture of organolead and inorganic lead compounds (Pb, trimethyllead and triethyllead) using reversed-phase HPLC. Mobile phase, 0.1 M ammonium acetate and 0.1 M acetic acid at pH 4.6, 30%...

Metallic lead is soft, bluish white, highly malleable, and ductile. It is a poor conductor of heat and electricity and resistant to corrosion. A protective film of basic carbonate is formed on the surface of lead exposed to moist air. Lead reacts with water in the presence of air to form lead hydroxide. Inorganic Pb(II) compounds are mainly insoluble or slightly soluble in water. Exceptions are lead chlorate, perchlorate, nitrate, and acetate. Lead chloride is moderately soluble (9.9 g/liter at 20°C). The most important organolead compounds are tetramethyllead and tetraethyllead used as antiknock additives in fuel. Both are colorless liquids at room temperature with boiling points 110 and 200°C, respectively. Photolytically these degrade to RaPb , R2Pb , and Pb. The different chemical forms of lead have different toxicity, so that speciation information is important [1,2]. 

Chau et al pointed out that as the authenticity of the compounds to be analyzed must be preserved, any of the digestion methods with acids or alkalis are not suitable, and that extraction seemed to be the method of choice for removing these compounds from samples. For this traction, they adopted benzene as recommended by Sirota and Uthe for the quantitative extraction of tetramethyllead and tetraethyllead from fish homogenates suspended in aqueous EDTA solution. Although ionic forms of lead such as Pb(II), diethyllead dichloride, and trimethyllead acetate do not extract in the benzene phase, any lead compounds that distribute into the benzene phase as tetraalkyllead will be determined. Chau et al421 found that environmental samples can contain other forms of organolead compounds that are extractable into benzene but which are not volatile enough to be analyzed by the GC-AAS technique, hence the need for a speciation specific analytical system. 

Other experiments indicated that conversion of lead(ll) compounds to Pb(CH3)4 was inconsistent and time-independent [130]. Lead contained in mine tailings is not mobilized in detectable amounts by biomethylation [125, 130]. A volatile organolead compound, presumably the methyllead derivative, was observed upon aerobic, not upon anaerobic, incubation of marine sediment with lead(ll) acetate [131]. Marine sediments inoculated with (CH3)3PbOOCCH3 produced Pb(CH3)4 in experiments employing flow-through conditions both under anaerobic and aerobic conditions. Production under anaerobic conditions was approximately threefold greater [130]. 

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